fix: detect Vite port for TanStack Start and validate redirect URI port

[nicknisi]

What

• detectPort now parses vite.config.{ts,js,mjs} first for TanStack Start projects (via a shared parseViteConfigPortFromDir helper), falling back to the legacy app.config.ts parsing.
• All three JS redirect validators (Next.js, React Router, TanStack Start) now compare the WORKOS_REDIRECT_URI port against the detected dev port on local hosts and report a mismatch as a validation error — "Validation passed" no longer renders over a broken install.
• Route-mismatch remediation hints use the actual redirect-URI origin instead of a hardcoded localhost:3000.

Why

From Akshay Maniyar's AuthKit friction log: on a Lovable-style TanStack Start app (Vite dev server on 8080, port configured only in vite.config.ts), the installer wrote port 3000 into .env.local and the dashboard (redirect URI, CORS origins, homepage), then reported "Validation passed" because the validators parsed the redirect URI and discarded the port. Login redirected to a dead port with a green checkmark on the install.

Testing

• New port-detection.spec.ts fixture cases for the vite.config shape (ts/js/mjs, legacy app.config precedence preserved).
• New validator cases: redirect-URI port mismatch flips validation to failed for all three frameworks.
• Pre-fix verification: the 11 new regression tests were confirmed to fail on the pre-fix code (stash check) and pass with the fix.
• Full gate: pnpm build && pnpm test && pnpm typecheck green.

---

Stack 1/7 (akshay-friction-log): this is the base PR — merges directly to main. The rest of the stack follows.

[greptile-apps]

Greptile Summary

This PR updates dev-port detection and redirect URI validation for JS framework installs. The main changes are:

• TanStack Start now checks vite.config.{ts,js,mjs} before the legacy app.config port.
• Shared Vite port detection is reused for React, React Router, Vanilla JS, and TanStack Start.
• Next.js, React Router, and TanStack Start validators now fail local redirect URI port mismatches.
• Route mismatch hints now use the redirect URI’s actual origin instead of localhost:3000.

Confidence Score: 5/5

Safe to merge with low risk.

The changes are narrowly scoped to port detection and validation messaging, with focused tests for the updated TanStack Start, Vite, and redirect URI mismatch behavior.

No files require special attention.

T-Rex Logs

What T-Rex did

• Ran the regression port-validation proof with Vitest and captured a log showing the command, working directory, Vitest output, and exit code 0.
• Ran the TypeScript typecheck proof and captured its log showing the command, working directory, TypeScript output, and exit code 0.
• Validated both logs confirm successful completion, indicated by exit codes 0 in each proof.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
src/doctor/checks/framework.spec.ts	Adds coverage confirming TanStack Start framework detection reports the Vite-configured dev port.
src/lib/port-detection.spec.ts	Adds tests for TanStack Start Vite port parsing, legacy fallback behavior, and shared Vite framework defaults.
src/lib/port-detection.ts	Refactors Vite port detection into a shared helper and applies it before legacy TanStack Start config parsing.
src/lib/validation/validator.spec.ts	Adds redirect URI port mismatch and origin-aware route hint tests across supported JS framework validators.
src/lib/validation/validator.ts	Adds local redirect URI port validation against detected dev ports and uses the configured redirect origin in route mismatch hints.

Sequence Diagram

%%{init: {'theme': 'neutral'}}%%
sequenceDiagram
participant Validator as validateInstallation
participant Framework as Framework-specific redirect validator
participant Port as detectPort
participant Config as Project config files
participant Issues as Validation issues

Validator->>Framework: validate redirect URI
Framework->>Framework: parse WORKOS redirect URI
Framework->>Port: detectPort(framework, projectDir)
Port->>Config: read vite.config / app.config / package.json
Config-->>Port: configured port or default
Port-->>Framework: detected dev port
Framework->>Framework: compare local URI port to detected port
alt port mismatch
    Framework->>Issues: add error issue
else port matches or non-local host
    Framework-->>Validator: continue route validation
end

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%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
sequenceDiagram
participant Validator as validateInstallation
participant Framework as Framework-specific redirect validator
participant Port as detectPort
participant Config as Project config files
participant Issues as Validation issues

Validator->>Framework: validate redirect URI
Framework->>Framework: parse WORKOS redirect URI
Framework->>Port: detectPort(framework, projectDir)
Port->>Config: read vite.config / app.config / package.json
Config-->>Port: configured port or default
Port-->>Framework: detected dev port
Framework->>Framework: compare local URI port to detected port
alt port mismatch
    Framework->>Issues: add error issue
else port matches or non-local host
    Framework-->>Validator: continue route validation
end

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_{Reviews (1): Last reviewed commit: "fix: detect Vite port for TanStack Start..." | Re-trigger Greptile}

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.

[nicknisi]

Closing in favor of a single combined PR from nicknisi/akshay.